Page 11 - CleanScience_Fall22
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   Figure 3. Laminate flooring construction with multiple layers. Source:
Figure 4. Horizontal and vertical bamboo flooring orienta- tion. Source:, a trading name for Kitchner Flooring LTD.
pressure into a solid block. The block is cut into planks creating a random appearance.
Materials and Methods
Two moisture exposure scenarios were examined using a solid wood􏰀􏰁ramed test apparatus that 􏰁eatured la􏰂ers o􏰁 􏰃􏰄􏰀gauge clear pol􏰂􏰅in􏰂l chloride 􏰆􏰇􏰈􏰉􏰊 sheeting. A base shelf was constructed inside the apparatus chamber that supported a smooth, 2 foot by 3 foot by 􏰃.􏰋 inch􏰀thick concrete slab 􏰆2,􏰋􏰌􏰌 psi􏰊, for water and test specimens. The chamber interior was maintained at an ambient temperature of 74°F with a relative humidity over 􏰍􏰋􏰎 using a stone bubbler diffuser sub􏰀 merged in a small tank of water suspended inside the chamber. The base shelf was lined with 􏰇􏰈􏰉 sheeting and a layer of 3.5 mil clear polyethylene. Water was initially added manually during both moisture expo􏰀 sure scenarios to maintain the desired water level using a slow􏰀drip system. The water level was maintained daily (Photo 1).
The wood 􏰏ooring test specimens were obtained from samples offered in the 􏰏ooring departments of Home Depot and Lowe’s building supply stores. The specimens were prepared in near adherence to ASTM Method G1. Manufacturer labels were removed by hand and specimens were cleaned lightly with soap and water followed by isopropyl alcohol to remove surface contaminants (􏰐􏰑􏰒􏰑􏰓 􏰔ngerprints, label adhesives
Photo 1. Test chamber with base shelf supporting concrete slab and specimens during experiment one.
Photo 2. This hardwood flooring exemplar (rift sawn) (Day 6) was the only exemplar that did not exhibit cupping after 142 days exposure to damp concrete.
and manufacturing residues). 􏰕itrile gloves were used during specimen handling.
The specimens were placed directly onto the con􏰀 crete surface inside the chamber for both moisture exposure scenarios. The concrete slab was fully satu􏰀 rated for 142 days during the 􏰔rst exposure scenario􏰖 however, no liquid water was visible on the concrete surface to prevent direct contact between the wood 􏰏ooring surface and liquid water. The concrete slab was fully saturated for 110 days with the specimens partially immersed to a depth (3􏰗4 mm) suf􏰔cient to prevent 􏰏oating. The 􏰔rst and second studies examined 12 and 1􏰘 different wood 􏰏ooring specimens, respec􏰀 tively. Each study included specimens representing the four predominant 􏰏ooring types.
Experiment One: Wood Flooring Exposed to a Damp Concrete Floor
Three observations were documented during examina􏰀 tions of wood 􏰏ooring exemplars􏰙 cupping, underside mold growth and visible changes in topside surface appearance. 􏰉upping was the 􏰔rst visible change
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